Welcome Here is this Keuffel & Esser K&E New York NY Polyphase Vtg Slide Rule Leather Case Made in USA pat. Small part needs to be glued as shown in photo. The item "Keuffel & Esser K&E New York NY Polyphase Vtg Slide Rule Leather Case USA 1900" is in sale since Saturday, July 12, 2014. This item is in the category "Collectibles\Science & Medicine (1930-Now)\Engineering\Slide Rules". The seller is "air_flight_museum" and is located in Flight Station. This item can be shipped worldwide.